フリーサイズ

noun which may take the genitive case particle 'no', noun

one-size-fits-all; free size

Wasei-eigo term used for clothing and accessories that are designed to fit a wide range of body sizes without specific size options.

wasei-eigo (Japanese-coined English), from free size

• この帽ぼう子しはフリーサイズなので、誰だれでもかぶれます。

  This hat is one-size-fits-all, so anyone can wear it.

• フリーサイズの靴くつ下したを買かったら、思おもったより大おおきかった。

  I bought free-size socks, but they were bigger than I expected.